Stringer module for self-supporting stairs

ABSTRACT

A stringer module for a self-supporting modular stairway in which each riser is composed of two modules (A), each module being manufactured from sheet metal, each module having an L-shape defining a base portion and a riser portion located at a first side of the base portion, whereby an overlap of the riser portion with an opposed part of the base portion of an adjacent like module defines a vertical riser of said stairway and the remaining base portion its tread. The riser portion is located above the base portion, the plane of the riser portion is folded to be offset relative to the base portion such that the base portions of adjacent modules are coplanar when overlapped. The overlapping portions of each module are provided with a series of horizontal slots on one portion and corresponding series of holes on the other portion, adjacent modules being secured in overlapping position by means of retractable pin-keys (B) engaging the holes and slots. The arrangement of slots and holes is such as to allow an adjustable positioning of the overlapping modules in both horizontal and vertical directions.

PREAMBLE

The present invention relates to the field of modular prefabricated stairs for indoor and outdoor use. The above solution envisages the adjustment of its characteristic parameters according to the regulations of the industry.

EXISTING SOLUTIONS

The reference field has a wide variety of solutions that can be summarised in two distinct categories:

the customised structures;

the modular structures.

The customised structures have several advantages including that of being created specifically for every environment. It is also true that these types of stairs consist of pieces of considerable size and weight, manufactured in the workshop, resulting of difficult transportation, both from the workshop to the place of assembly, and within the installation location thereof (for example, assembly in the upper floors of a condominium building). Moreover, it can easily be imagined that in most cases this type of structures has not been subjected to analysis of capacity or any other engineering calculation in order to be able to state that the stairs meets the regulations in force. In addition, the time for manufacturing this stairs is long and the resulting cost is higher compared to a modular structure. It can therefore be stated that the customised stairs is good looking, but of difficult handling and high costs.

The modular structure is submitted to the market exactly for avoiding the limitations of the customised structure, mainly against the inconvenience in transportation and the high cost. The solutions currently in the market of modular structures differ from those non-adjustable and those adjustable. The first has the adjustment limit that cannot be carried out. The pieces must be modified in most cases during assembly and this lengthens installation time besides increasing the cost of a structure which in the first place appears convenient. The second is adjustable, but in most cases only in one of the two directions: either height, or length. The possibility of adjustment is to the detriment of aesthetics of the structure which has a considerable number of pieces, mostly in full view (screws, spacers, etc.).

In particular, the invention is represented in the following Figures:

TABLE 1: VIEW OF LAY-OUT

TABLE 2: EXAMPLE OF COUPLED MODULES

TABLE 3: EXPLODED INNER VIEW

A: LATERAL SIDE

B: PIN-KEY

C: WASHER

D: FASTENING SCREW

TABLE 4: EXPLODED OUTER VIEW

TABLE 5: MODULE

E: SECTION

The structure, object of the patent (TABLE 1), consists of a modular stairs, adjustable, with two side fascias.

The possibilities of adjusting the stairs are in both directions, both in height and in length, maintaining in all cases compliance with the regulations in force. The module is manufactured by folding a metal sheet which allows, thanks to the adopted shape after processing, the exact alignment of the entire structure. The characteristic part of the invention is the assembly of the two modules that make up the load-bearing part of the structure.

The height (or rise) is determined by the positioning of pins-keys inserted in the lower part of the module, inner side (TABLE 3). The length (or tread) is determined by the coupling of the above-mentioned pins-keys with the special precision slots located in the upper part, outer side, of the next module (TABLE 4).

These characteristic parameters of any whatsoever structure can vary due to the different available positions.

What distinguishes this modular stairs is the clean aesthetics thanks to absence on the outer side of bolts and screws and various components, and above all, use of few components for its manufacture.

ASSEMBLY

The fundamental innovation is the simplicity of assembly of the details. In fact, as shown in TABLE 3 and TABLE 4, assembly between two modules is carried out in just three simple steps:

1. Fastening of two pins-keys in the lower inner part of the first module.

2. Coupling of the pin-key part that protrudes from the first lateral side, with the precision slots that are located in the upper outer part of the second module.

3. Locking of the two modules by closing with fastening screw and washer in the pre-set oval hole. 

1. A stringer module for a self-supporting modular stairway in which each riser is composed of two spaced-apart modules (A), each module being manufactured from sheet metal or an extruded aluminium alloy, each module having an L-snape of equal thickness defining a base portion and a riser portion located at a first side of the base portion, whereby an overlap of the riser portion with an opposed part of the base portion of an adjacent like module defines a vertical riser of said stairway and the remaining base portion its tread, characterised in that the riser portion is located above the base portion, the plane of the riser portion is folded to be offset relative to the base portion such that the base portions of adjacent modules are coplanar when over-lapped, the overlapping portions of each module are provided with a series of horizontal slots on one portion and corresponding series of holes on the other portion, adjacent modules are secured In overlapping position by means of retractable pin-keys (B) located in said holes and cooperating with said slots, the arrangement of slots and holes being such as to allow an adjustable positioning of the overlapping modules in both horizontal and vertical directions, and the overlapping modules are locked together by means of fastening screws (D) and washers (C).
 2. Structure according to the preceding claims, characterised in that the folding is made towards the inner the structure itself and in the upper part of the lateral side.
 3. Structure according to claim 2, characterised in that the a riser portion, located at a first side of the base portion of a module, overlaps in a base portion of next module.
 4. Structure according to the preceding claims, characterised in that on the outer upper part are located the blind holes precision slots for the adjustment of the characteristic parameters.
 5. Structure according to claim 4, characterised in that on the inner bottom part of the lateral side are located the blind holes, for adjustment according to the regulations in force, of the structure thereof.
 6. Structure according to claim 1, characterised in that the pins-keys are in Steel.
 7. Structure according to claim 1, characterised in that the washers are in Steel.
 8. Structure according to claim 1, characterised in that the fastening screws are in Steel.
 9. Structure according to claims 1, 4 and 6, characterized in that the pins-keys are applied in two blind holes on the Inner lower part of the lateral side and coupled with the relating precision slots on the outer upper part of the next lateral side.
 10. Structure according to claims 1, 5 and 6, characterised in that the fastening screw is applied in the Inner part of the module and with the washer locking the two lateral sides together in the oval hole, positioned in the upper part of the module. 